1Anesthesia Center for Critical Care Research of the Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, 2Cardiovascular Research Center and Cardiology Division of the Department of Medicine, Massachusetts General Hospital, 3Cardiovascular Division, Brigham and Women's Hospital, 4Harvard Medical School, 5Department of Anesthesiology, Uniklinik RWTH Aachen, RWTH Aachen University, 6Center for Immunology and Inflammatory Diseases and the Division of Rheumatology, Allergy, and Immunology of the Department of Medicine, Massachusetts General Hospital

1Departments of Physiology, Medical College of Wisconsin, 2Human and Molecular Genetics Center, Medical College of Wisconsin, 3Cardiovascular Center, Medical College of Wisconsin, 4Blood Research Institute of Wisconsin

1School of Biomedical Science, The Ohio State University College of Medicine, 2Center for Cardiovascular and Pulmonary Research, The Research Institute at Nationwide Children's Hospital, 3Department of Pediatrics, The Ohio State University College of Medicine

1Department of Orthopaedic Surgery, University of Michigan Medical School, 2Department of Molecular & Integrative Physiology, University of Michigan Medical School, 3Department of Biomedical Engineering, University of Michigan Medical School, 4Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School

1Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 2Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 3Department of Molecular Biophysics and Physiology, Rush University Medical Center, 4Department of Internal Medicine, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center

1Stem Cell Research Center, Department of Bioengineering and Orthopedic Surgery, University of Pittsburgh, 2Department of Orthopedic Surgery, University of Pittsburgh, 3Nazarbayev University Research and Innovation System, Nazarbayev University, 4Department of Orthopaedic Surgery, UCLA Orthopaedic Hospital and the Orthopaedic Hospital Research Center, University of California at Los Angeles, 5Department of Cell Biology, Erasmus MC Stem Cell Institute, 6OHSU Center for Regenerative Medicine, Oregon Health & Science University, 7Centre for Cardiovascular Science and MRC Centre for Regenerative Medicine, Queen's Medical Research Institute and University of Edinburgh, 8David Geffen School of Medicine and the Orthopaedic Hospital Research Center, University of California at Los Angeles, 9Stem Cell Research Center, Department of Orthopedic Surgery and McGowan Institute for Regenerative Medicine, University of Pittsburgh

1Department of Biochemistry, Medical College of Wisconsin, 2Stanford Cardiovascular Institute, Stanford University School of Medicine, 3Department of Anesthesiology, Medical College of Wisconsin, 4Stem Cell and Regenerative Medicine Consortium, LKS Faculty of Medicine, Hong Kong University, 5Division of Cardiology, Johns Hopkins University School of Medicine, 6Cardiovascular Research Center, Biotechnology and Bioengineering Center, Medical College of Wisconsin

1Division of Drug Delivery and Tissue Engineering, University of Nottingham, 2Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, 3Division of Immunology and Allergy, School of Molecular Medical Sciences, University of Nottingham, 4Division of Respiratory Medicine, School of Clinical Sciences, University of Nottingham, 5NIHR Respiratory Biomedical Research Unit, University of Leicester, 6School of Sport, Exercise, and Health Sciences, Loughborough University

Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation technique that involves passing current through an insulated coil placed against the scalp. A brief magnetic field is created by current in the coil, and because of the physical process of induction, this leads to a current in the nearby neural tissue. Depending on the duration, frequency, and magnitude of these magnetic pulses, the underlying neural circuitry can be affected in many different ways. Here, we demonstrate the technique of single-pulse TMS, in which one brief magnetic pulse is used to stimulate the neocortex.
One observable effect of TMS is that it can produce muscle twitches when applied over the motor cortex. Due to the somatotopic organization of the motor cortex, different muscles can be targeted depending on the precise placement of the coil. The electrical signals that cause these muscle twitches, called motor evoked potentials, or MEPs, can be recorded and quantified by electrodes placed on the skin over the targeted muscle. The amplitude of MEPs can be interpreted to reflect the underlying excitability of the motor cortex; for example, when the motor cortex is activated, observed MEPs are larger. …